I don't understand that model, tbh, not with the vast majority of those at high risk of hospitalisation now double-jabbed. I see the early evidence suggesting strongly the reverse. Places like Bolton and Bedford that were hit early appear, tentatively, to be past their local peaks, and without a massive surge in hospitalisation or deaths.
My back of an envelope calculation puts the effective R number reducing by around 5 per cent per week due to ongoing vaccinations, that percentage going up a bit each week as we edge towards completion. (Working on 3.5 million vaccinations a week, around 70 million more vaccinations to do the entire population, assuming that each vaccination equals 0.5 protection.)
I'll try to be briefer than I normally am when discussing models etc with you, I'll just whack out a partial skeleton and you can choose which bits you want to discuss further.
Its not one model, its lots of models including amateur modelling attempts online. But every one of these models is capable of generating a number of very different results, and sometimes the changes to size of wave can be large with only a small adjustment to input parameters.
Possible reasons for not understanding how the hospitalisation rates can still end up so large in the current circumstances:
Not appreciating quite how large the number of daily cases could become in this wave.
Not appreciating quite how many people in ages younger than the eldest groups are still at risk of hospitalisation. A new set of data for hospitalisations in England by age group is due out in 3 days and I will no doubt use that to make some points as soon as I can.
Not appreciating how many vaccinated people are still expected to be hospitalised in the event of a significant wave of infections.
Not having factored in all of the estimates about Deltas capabilities compared to previous variants.
I dont do my own R calculations but when I get a chance I will try to point out some stuff I've seen other people doing on this front on twitter.
It is true that data from places like Bolton has given some people cause for optimism. Its too soon for me to join that club, but I have noted what they are on about. If I knew that the turnaround seen in such places will be fully sustained, and that no other location would show a worse pattern, I could join that club. Sadly it takes much longer for those matters to be settled than we've had so far, at least as far as Im concerned.
Finally I'll just say that there is significantly more uncertainty in my own view of the future and the magnitude of this new wave than I have experienced at any previous point in the pandemic. This is due to the combination of immunity through prior infection and immunity via vaccination, coupled with all the variables relating to the Delta strain. I do not exclude the possibility that this wave will be modest, but for all sorts of reasons I cannot possibly exclude the much worse possibilities either, and when I try to drill down into the detail and understant the models etc, these bad possibilities still make sense to me, they dont seem implausible.